Data transmission system, data transmission method, and electronic apparatus

ABSTRACT

A data transmission system, a data transmission method and an electronic equipment. In the playback system, by a controller, at step S1, SEID with respect to receiving stream is grasped. At step S2, inquiry command is used to designate SEID to inquire corresponding Bluetooth output plug No. At step S3, the grasped Bluetooth output plug No. is designated to inquire connecting destination within target of this Bluetooth output plug. Further, in the playback system, by the controller, at step S4, operating state of subunit serving as signal source is inquired. At step S5, information indicating signal source of stream is displayed on a display unit.

TECHNICAL FIELD

This invention relates to a data transmission system and a datatransmission method for transmitting and receiving stream by pluralelectronic equipments, and an electronic equipment constituting a datatransmission system for transmitting and receiving stream by pluralelectronic equipments.

BACKGROUND ART

In recent years, there has been proposed a system in which AV (AudioVideo) equipments such as CD (Compact Disc) player or digital video,etc. is connected through network to transmit or receive audio stream orvideo stream. As network for realizing such a system, there is, e.g.,network in which AV equipments are connected by serial bus in conformitywith the IEEE 1394 where various standards are drafted with IEEE Std.1394-1995: IEEE Standard for a High Performance serial Bus recognized byIEEE (Institute of Electrical and Electronics Engineers) being as thefundamental specification.

In the IEEE 1394, AV/C (Audio Video/Control) command is employed ascommand set in protocol in which content relating to control of AVequipment is defined. In addition, in the IEEE 1394, setup intransmission of AV signal and transmission packet format are prescribedin IEC (International Electrotecchnical Commission) 61883, andmanagement of logical connection and disconnection between equipments iscarried out in conformity with connection management in accordance withthis IEC 61883.

In such IEEE 1394, with respect to flow of stream within the equipment,Plug Control Register (hereinafter abbreviated as PCR) defined in theIEC 61883 is used to carry out management of logical input/output portfor carrying out input/output of data. On the other hand, in the IEEE1394, with respect to flow of stream between different equipments, AV/Cserial bus plug defined in the AV/C command is used to carry outmanagement of logical input/output port for carrying out input/output ofdata. Further, in the IEEE 1394, these PCR and AV/C serial bus plug arecaused to have one-to-one correspondence. For this reason, in the IEEE1394, connection is established, e.g., between plug of subunit servingas source of data and plug of unit so as to have one-to-onecorrespondence, and correspondence between flow of stream within theequipment and flow of stream between equipments becomes clear.Accordingly, control of the entirety of the system is facilitated.

Meanwhile, in recent years, as one technology of short range wirelesscommunication standard which has been developed in order to mutuallycarry out wireless connection of portable terminal machine andperipheral equipment thereof, attention is drawn to Bluetooth™ WirelessTechnology. Further, in recent years, there has been tried a method inwhich Bluetooth Wireless Technology is applied to AV equipment to carryout wireless communication of audio stream or video stream.

In such Bluetooth specification, two protocols, i.e., protocol calledAVCTP (AV Control Transport Protocol) and protocol called AVDTP (AVDistribution Transport Protocol) are prescribed The AVCTP is protocol inthe Bluetooth in which content relating to control of AV equipment isdefined, and the above-described AV/C command is employed similarly tothe IEEE 1394 as command set in the AVCTP. On the other hand, the AVDTPis protocol in the Bluetooth specification in which content relating totransmission of AV signal is defined, and is protocol corresponding toconnection management in accordance with the above-described IEC 61883.

These AVCTP and AVDTP are protocols independent each other. For thisreason, in the Bluetooth application, in such cases that, e.g.,transmission of AV signal is not carried out, but operation control ofAV equipment is carried out merely by remote control, if only AVCTP isused, it is possible to control the AV equipment. On the other hand, insuch cases that the AV equipment is not controlled, but transmission ofAV signal is merely carried out, if only AVDTP is used, it is possibleto carry out transmission of AV signal.

However, in the Bluetooth specification, there is no relevance betweeninterface with respect to stream within the equipment which is definedat the side of AVCTP and interface with respect to stream betweenequipments which is defined at the side of AVDTP.

For this reason, in the Bluetooth application, even if, e.g., audiostream or video stream can be received, equipment of that receiving sidecould not recognize signal source of stream. In more practical sense, inthe case where equipment of the transmitting side of stream employsplural subunits as signal source, when, e.g., equipment of thetransmitting side has two signal sources of player and tuner, theequipment of the receiving side could receive stream from theserespective signal sources, but could not recognize that received streamis outputted from any signal source. Accordingly, the equipment of thereceiving side could not notify information of signal source to user bydisplay, etc. As described above, the system to which Bluetoothspecification is applied could not carry out control of the entirety ofthis system. As a result, convenience was injured for user.

In addition, in the Bluetooth specification, procedure when connectionis given is prescribed between equipment of the transmitting side andequipment of the receiving side by AVDTP. Accordingly, in the Bluetoothspecification, while control could be carried out in connection withmutual connection by these two equipments, it was impossible that thethird equipment except for the two equipments is caused to be controllerto control connection between these two equipments.

DISCLOSURE OF THE INVENTION

This invention has been made in view of such circumstances, and itsobject is to provide a data transmission system, a data transmissionmethod and an electronic equipment in which interface with respect tostream within the equipment and interface with respect to stream betweenequipments are caused to be related to each other so that control ofstream can be carried out. In addition, another object of this inventionis to provide a data transmission system and a data transmission methodwhich can control connection between two equipments by equipment exceptfor the two equipments which carry out transmission/reception of data,and an electronic equipment capable of controlling connection betweentwo equipments which carry out transmission/reception of data.

A data transmission system according to this invention which attains theabove-described objects is directed to a data transmission system forcarrying out transmission/reception of stream by wireless-connectedplural electronic equipments, wherein a first electronic equipment whichtransmits stream comprises one or plural signal generating means servingas signal source of stream, and a second electronic equipment whichreceives stream grasps either one of identifier for identifyinginterface with respect to stream within the first electronic equipmentoutputted from the one or plural signal generating means and identifierfor identifying interface with respect to stream between the secondelectronic equipment and the first electronic equipment, and comprisescommand generating means for generating command for making an inquirywith respect to the first electronic equipment about mapping of the oneidentifier which has been grasped and the other identifier which has notbeen grasped on the basis of the one identifier which has been grasped,and response analysing means for analysing response indicatinginformation of the other identifier transmitted from the firstelectronic equipment.

Such data transmission system according to this invention makes aninquiry with respect to the first electronic equipment about mapping ofthe one identifier which has been grasped and the other identifier whichhas not been grasped on the basis of the one identifier which has beengrasped by the second electronic equipment to carry out correlatingbetween one identifier and the other identifier.

Moreover, a data transmission method according to this invention whichattains the above-described objects is directed to a data transmissionmethod of carrying out transmission/reception of stream bywireless-connected plural electronic equipments, wherein a secondelectronic equipment which receives the stream grasps either one ofidentifier for identifying interface with respect to stream within afirst electronic equipment which transmits the stream outputted from oneor plural signal generating means serving as signal source of streamthat the first electronic equipment has and identifier for identifyinginterface with respect to the stream between the first electronicequipment and the second electronic equipment, the data transmissionmethod comprising: a command generation step of generating command whichmakes an inquiry with respect to the first electronic equipment aboutmapping of the one identifier which has been grasped and the otheridentifier which has not been grasped on the basis of the one identifierthat the second electronic equipment has grasped by the secondelectronic equipment, and a response analysis step of analysing responseindicating information of the other identifier transmitted from thefirst electronic equipment by the second electronic equipment.

Such data transmission method according to this invention makes aninquiry with respect to the first electronic equipment about mapping ofone identifier which has been grasped and the other identifier which hasnot been grasped on the basis of the one identifier which has beengrasped by the second electronic equipment to carry out correlatingbetween one identifier and the other identifier.

Further, an electronic equipment according to this invention whichattains the above-described objects is directed to an electronicequipment which is wireless-connected to other electronic equipment andis capable of receiving stream transmitted from the other electronicequipment, wherein the electronic equipment grasps either one ofidentifier for identifying interface with respect to stream within theother electronic equipment outputted from one or plural signalgenerating means serving as signal source of stream that the otherelectronic equipment has and identifier for identifying interface withrespect to stream between the electronic equipment and the otherelectronic equipment, and comprises command generating means forgenerating command which makes an inquiry with respect to the otherelectronic equipment about mapping of the one identifier which has beengrasped and the other identifier which has not been grasped on the basisof the one identifier which has been grasped, and response analysingmeans for analysing response indicating information of the otheridentifier transmitted from the other electronic equipment.

Such electronic equipment according to this invention makes an inquirywith respect to the other electronic equipment about mapping of oneidentifier which has been grasped and the other identifier which has notbeen grasped on the basis of the one identifier which has been graspedto carry out correlating between one identifier and the otheridentifier.

Furthermore, a data transmission system according to this inventionwhich attains the above-described objects is directed to a datatransmission system for carrying out transmission/reception of stream byplural electronic equipments, the data transmission system comprising afirst electronic equipment for transmitting or receiving the stream, asecond electronic equipment which is wireless-connected to the firstelectronic equipment and is capable of receiving or transmitting thestream, and a third electronic equipment for generating command whichselects the second electronic equipment in accordance with the firstelectronic equipment to instruct the first electronic equipment toconnect to the second electronic equipment.

Such data transmission system according to this invention allows thethird electronic equipment to select the second electronic equipment inaccordance with the first electronic equipment to instruct the firstelectronic equipment to connect to the second electronic equipment.

Further, a data transmission method according to this invention whichattains the above-described objects is directed to a data transmissionmethod of carrying out transmission/reception of stream by pluralelectronic equipments, the data transmission method comprising a commandgeneration step of generating command which selects, by a thirdelectronic equipment, a second electronic equipment which iswireless-connected to a first electronic equipment which transmits orreceives the stream and is capable of receiving or transmitting thestream in accordance with the first electronic equipment to instruct thefirst electronic equipment to connect to the second electronic equipmentby the third electronic equipment.

Such data transmission method according to this invention allows thethird electronic equipment to select the second electronic equipment inaccordance with the first electronic equipment to instruct the firstelectronic equipment to connect to the second electronic equipment.

Further, an electronic equipment according to this invention whichattains the above-described objects is directed to an electronicequipment constituting a data transmission system adapted for carryingout transmission/reception of stream by plural electronic equipments,the electronic equipment comprising command generating means forgenerating command which selects, in accordance with a first electronicequipment for transmitting or receiving the stream, a second electronicequipment which is wireless-connected to the first electronic equipmentand is capable of receiving or transmitting the stream to instruct thefirst electronic equipment to connect to the second electronicequipment.

Such electronic equipment according to this invention selects the secondelectronic equipment in accordance with the first electronic equipmentto instruct the first electronic equipment to connect to the secondelectronic equipment.

Furthermore, a data transmission system according to this inventionwhich attains the above-described objects is directed to a datatransmission system for carrying out transmission/reception of stream byplural electronic equipments, the data transmission system comprising afirst electronic equipment for transmitting or receiving the stream, asecond electronic equipment which is wireless-connected to the firstelectronic equipment and is capable of receiving or transmitting thestream, and a third electronic equipment for generating command todiscover an electronic equipment or equipments in which connection canbe made with respect to the first electronic equipment.

Such data transmission system according to this invention gives, by thethird electronic equipment, an instruction so as to discover anelectronic equipment or equipments in which connection can be made withrespect to the first electronic equipment.

Further, a data transmission method according to this invention whichattains the above-described objects is directed to a data transmissionmethod of carrying out transmission/reception of stream by pluralelectronic equipments, the data transmission method comprising a commandgeneration step of generating command to discover an electronicequipment or equipments in which connection can be made with respect toa first electronic equipment for transmitting or receiving the stream bya third equipment which is different from the first electronic equipmentand a second electronic equipment which is wireless-connected to thefirst electronic equipment and is capable of receiving or transmittingthe stream.

Such data transmission method according to this invention gives, by thethird electronic equipment, an instruction so as to discover anelectronic equipment or equipments in which connection can be made withrespect to the first electronic equipment.

In addition, an electronic equipment according to this invention whichattains the above-described objects is directed to an electronicequipment constituting a data transmission system for carrying outtransmission/reception of stream by plural electronic equipments,wherein the electronic equipment is different from a first electronicequipment for transmitting or receiving stream and a second electronicequipment which is wireless-connected to the first electronic equipmentand is capable of receiving or transmitting the stream, the electronicequipment comprising command generating means for generating command todiscover an electronic equipment or equipments in which connection canbe made with respect to the first electronic equipment.

Such electronic equipment according to this invention give aninstruction so as to discover an electronic equipment or equipments inwhich connection can be made with respect to the first electronicequipment.

Still further objects of this invention and more practical meritsobtained by this invention will become more apparent from thedescription of the embodiments which will be given.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view for explaining architecture of protocol prescribed inBluetooth specification.

FIG. 2 is a view for explaining AV/C unit model.

FIG. 3 is a view for explaining the configuration of asynchronous packetin which command caused to undergo transmission/reception in the AV/C isstored.

FIG. 4 is a view for explaining the configuration of command framecaused to be in capsule form with respect to FCP frame in theasynchronous packet shown in FIG. 3.

FIG. 5 is a view for explaining the configuration of response framecaused to be in capsule form with respect to FCP frame in theasynchronous packet shown in FIG. 3.

FIG. 6 is a view for explaining architecture of AVDTP.

FIG. 7 is a view for explaining the configuration of an example of AVdevice, and is a view for explaining stream end point.

FIG. 8 is a view for explaining the configuration of playback(reproduction) system shown as the embodiment of this invention.

FIG. 9 is a block diagram for explaining the configuration of theplayback (reproduction) system.

FIG. 10 is a view for explaining unit model in which AV/C unit model isextended.

FIG. 11 is a view for explaining the configuration of command frame ofinquiry command by the first definition for inquiring mapping of SEIDand Bluetooth-output plug No., and is a view for explaining theconfiguration of command frame of inquiry command for inquiringinformation relating to input plug.

FIG. 12 is a view for explaining the configuration of response framewith respect to the inquiry command shown in FIG. 11.

FIG. 13 is a view for explaining the configuration of command frame ofinquiry command by the first definition for inquiring mapping of SEIDand Bluetooth output plug No., and is a view for explaining theconfiguration of command frame of inquiry command for inquiringinformation relating to output plug.

FIG. 14 is a view for explaining the configuration of response framewith respect to the inquiry command shown in FIG. 13.

FIG. 15 is a view for explaining the configuration of command frame ofinquiry command in the case where Bluetooth-output plug No.corresponding to SEID is inquired.

FIG. 16 is a view for explaining the configuration of response framewith respect to the inquiry command shown in FIG. 15.

FIG. 17 is a view for explaining the configuration of command frame ofinquiry command in the case where information for identifying interfacewith respect to stream between equipments corresponding to general busoutput plug No. is inquired.

FIG. 18 is a view for explaining the configuration of response framewith respect to the inquiry command shown in FIG. 17.

FIG. 19 is a view for explaining the configuration of command frame ofinquiry command by the second definition for inquiring mapping of SEIDand Bluetooth output plug No., and is a view for explaining theconfiguration of command frame of inquiry command for inquiringinformation relating to input plug.

FIG. 20 is a view for explaining the configuration of response framewith respect to the inquiry command shown in FIG. 19.

FIG. 21 is a view for explaining the configuration of command frame ofinquiry command by the second definition for inquiring mapping of SEIDand Bluetooth output plug No., and is a view for explaining theconfiguration of command frame of inquiry command for inquiringinformation relating to output plug.

FIG. 22 is a view for explaining the configuration of response framewith respect to the inquiry command shown in FIG. 21.

FIG. 23 is a view for explaining the configuration of command frame ofinquiry command in the case where Bluetooth output plug No.corresponding to SEID is inquired.

FIG. 24 is a view for explaining the configuration of command frame ofinquiry command by the first definition for inquiring mapping of SEIDand Bluetooth output plug No.

FIG. 25 is a view for explaining the configuration of response framewith respect to the inquiry command shown in FIG. 24.

FIG. 26 is a view for explaining the configuration of command frame ofinquiry command by the third definition for inquiring mapping of SEIDand Bluetooth output plug No.

FIG. 27 is a view for explaining the configuration of response framewith respect to the inquiry command shown in FIG. 26.

FIG. 28 is a flowchart for explaining a series of processing steps inthe playback (reproduction) system, and is a flowchart for explaining aseries of processing steps when correlating between Bluetoothinput/output plug No. and SEID is carried out and information of signalsource of stream is obtained at the receiving side.

FIG. 29 is a view for explaining the configuration of command frame ofconnect command.

FIG. 30 is a block diagram for explaining the configuration of a datatransmission system shown as another embodiment of this invention.

FIG. 31 is a view for explaining the configuration of command frame ofcommand which discovers device in which connection can be made.

FIG. 32 is a view for explaining the configuration of response framewith respect to the command shown in FIG. 31.

FIG. 33 is a view for explaining the configuration of command frame ofcommand which establishes connection between two devices.

FIG. 34 is a flowchart for explaining a series of processing steps inthe data transmission system, and is a flowchart for explaining a seriesof processing steps when connection between two devices is controlled.

FIG. 35 is a block diagram for explaining another configuration of thedata transmission system shown as another embodiment of this invention.

BEST MODE FOR CARRYING OUT THE INVENTION

More practical embodiments to which this invention is applied will nowbe described in detail with reference to the attached drawings.

This embodiment is directed to a data transmission system for carryingout transmission/reception of audio stream and/or video stream by AV(Audio Video) equipment wireless-connected by Bluetooth WirelessTechnology. In this data transmission system, correlating betweeninterface with respect to stream within equipment and interface withrespect to stream between equipments is carried out, thereby making itpossible to carry out control of stream, and making it possible toobtain information of signal source of stream at the receiving side. Inaddition, in this data transmission system, when transmission/receptionof stream on Bluetooth link is carried out between two equipments,equipment except for the two equipments is caused to be controller, thusmaking it possible to control connection between two equipments by thiscontroller.

First, here, prior to the explanation of more practical datatransmission system, protocol prescribed in the Bluetooth specificationwill be described.

In the Bluetooth specification, as shown in FIG. 1, among two equipmentswhich carry out communication, equipment at the side of carrying outsetup of connection is called Initiator and equipment at the sideopposite thereto is called Acceptor. As protocol stack in the Bluetoothspecification, when roughly classified, there is employed a structure inwhich protocol called AVCTP (AV Control Transport Protocol) and protocolcalled AVDTP (AV Distribution Transport Protocol) are provided onPhysical layer and Data Link layer, and the Initiator and the Acceptorare mutually connected between respective layers in such protocol causedto be of hierarchical structure. It is to be noted that, in theBluetooth specification, at the Data Link layer, synchronouscommunication oriented communication link of the line switching typecalled SCO (Synchronous Connection Oriented) link and asynchronouscommunication oriented communication link of the packet switching typecalled ACL (Asynchronous Connection Less) link are defined. In theBluetooth specification, in the case where transmission of signal forwhich real time characteristic is required such as audio stream or videostream, etc. is carried out, SCO link is ordinarily used. However, inthis SCO link, in the case where error takes place, it is impossible tocarry out re-sending. In view of the above, in the Bluetoothspecification, in order to realize real time transmission even if thetransmission system is asynchronous communication, such an attempt ismade to superimpose so-called RTP which is time stamp used in internet,etc. on ACL link to thereby carry out transmission of audio stream orvideo stream by using the ACL link.

Here, two protocols, i.e., AVTCP and AVDTP will be described in detail.

The AVCTP is protocol in which content relating to control of AVequipment is defined, and there is employed AV/C (Audio Video/Control)command employed in the 1394 Trade Association in which variousstandards are drafted with IEEE Std. 1394·1995:IEEE Standard for a HighPerformance serial Bus recognized by IEEE (Institute of Electrical andElectronics Engineers) as command set in this AVCTP being as thefundamental specification. In the Bluetooth application, e.g., variouscommands such as Playback command, etc. and responses with respect torespective various commands are exchanged between the Controller and theTarget by using this AVCTP.

Here, in the AV/C, as shown in FIG. 2, set of equipments physicallyexisting is expressed by logic as unit, set existing at the lower rankconcept of this unit and for realizing logical function of equipment isexpressed as subunit, and unit existing at further lower rank conceptwith respect to the subunit and for realizing logical function isexpressed as function block although not shown as occasion demands. Theunit and the subunit are concept in which physical hardware and/orsoftware of equipment are included. Additionally, the function block maybe constituted only by software such as program, etc.

Further, in the AV/C, logical input/output port for carrying outinput/output of data is expressed as the concept called plug. In theAV/C, as plug used for isochronous transmission which is synchronouscommunication in the IEEE 1394, 31 Serial Bus Isochronous Input Plugsand 31 Serial Bus Isochronous Output Plugs are prescribed. As plug usedfor asynchronous transmission which is asynchronous communication in theIEEE 1394, 31 Serial Bus Asynchronous Input Plugs and 31 Serial BusAsynchronous Output Plugs are prescribed. As plug applied to networkexcept for the IEEE 1394 and used in practice for input/output of analogdata, 31 External Input Plugs and 31 External Output Plugs areprescribed. In the AV/C, these unit plugs provided at the unit andsubunit plugs (not shown) provided at the subunit are connected fixedlyor after undergo switching as occasion demands, whereby transmissionpath of stream within the equipment is established. It is to be notedthat while the example where two subunits are provided is indicated inthe figure, the number of subunits may be increased or decreased. Inthis invention, as described later, there are newly provided componentsfor carrying out transmission of data by general bus including Bluetoothnetwork as plug serving as interface with respect to stream withinequipment provided at unit.

Further, in the AV/C, command is transmitted from equipment serving ascontroller to respective equipments by asynchronous packet as shown inFIG. 3. The asynchronous packet has the configuration that, in additionto destination ID field (Destination_ID) indicating address of unit oftransmit destination and source ID field (Source_ID) indicating addressof unit of transmit source, after packet header consisting oftransaction label field (transaction label; tl), retry code field (retrycode; rt), transaction code field (transaction code; tcode), priorityfield (priority; pri), destination offset field (Destination_offset),data length field (Data_length), zero field (zero), and header CRC field(Cyclic Redundancy Check) (Header_CRC), there is continued data blockconsisting of FCP frame (Function Control Protocol frame) consisting ofcommand transaction set field (Command Transaction Set; cts), FCP datafield (Function Control Protocol data) and zero field (zero) as occasiondemands, and data CRC field (Data_CRC).

In the FCP frame, command and response are caused to be in capsule form.As shown in FIG. 4, command frame consists of the above-describedtransaction set field (Command Transaction Set; cts) indicating kind ofcommand set, command type field (Command type; ctype) indicating kind ofcommand, subunit type field (subunit_type) and subunit ID field(subunit_ID) for forming address of subunit of transmit destination,opcode field (opcode), plural operand fields (Operand), and zero field(zero) as occasion demands. On the other band, as shown in FIG. 5,response frame consists of command transaction set field (CommandTransaction Set; cts), response code field indicating kind of response(Response code; response), subunit type field (subunit_type) and subunitID field (subunit_ID) for forming address of subunit of transmit source,opcode field (opcode), plural operand fields (Operand), and zero field(zero) as occasion demands. Additionally, in the case of AV/C, withrespect to both command frame and response frame, “0000” is stored asvalue in the command transaction set field.

In the AV/C, information of equipment serving as target that equipmentserving as controller attempts to control, and/or information indicatingprocessing content to be controlled are stored with respect to commandframe, and information indicating processing content corresponding tocommand by equipment serving as target is stored with respect toresponse frame.

On the other hand, AVDTP is a protocol in which content relating totransmission of AV signal is defined, and is roughly classified into twosystems of signalling and streaming. In more practical sense, as shownin FIG. 6, the AVDTP intermediates between logical link management layer(Logical Link Control and Adaptation Protocol; L2CAP) in the data layerand application layer.

Signalling is carried out at the preceding stage of actual datatransmission, and is used, e.g., for discriminating format to whichequipment corresponds, or discriminating an equipment which can receivedata to be transmitted from the application layer to carry outnegotiation to set up connection with respect to the logical linkmanagement layer.

On the other hand, Streaming consists of Adaptation Layer, Recovery andStream management from the logical link management layer side. Theadaptation layer serves to include data for error correction or controldata, etc. with respect to stream from the application layer so thatpacket data is provided. Recovery serves to carry out resending in thecase where error takes place. Stream management carries out managementof the Adaptation Layer and the Recovery.

In the Bluetooth specification, prior to carrying out transmission ofdata between two equipments which carry out transmission/reception ofdata by using such AVDTP, transmission path of stream betweenequipments, i.e., connection is established by Signalling. At this time,interface in the equipment at the side for transmitting data is handledas Stream End Point. Namely, interface in the equipment at the side fortransmitting data is handled as termination of individual streams.

In more practical sense, in the Bluetooth specification, as the exampleof AV device is shown in FIG. 7, Bluetooth AV device as the applicationlayer and the logical link management layer channel (L2CAP channels) areconnected by signalling. When connection is established by thissignalling, interface of the Bluetooth AV device is handled as streamend point. Respective stream end points are caused to undergo managementas stream end point ID (Stream End point IDentifier which will bereferred to as SEID hereinafter). As described above, plug number isstatically assigned in such a manner that plug serving as interface withrespect to stream within the equipment is fixedly or suitably switched.On the contrary, in stream end point serving as interface with respectto stream between equipments, SEID is dynamically assigned every timeconnection is given. It is to be noted that while the example where twoSEIDs (SEID [1], SEID [2]) are provided is shown in the figure, thenumber of SElDs may be increased or decreased in accordance with thenumber of subunits serving as signal source.

Media Frames serving as actual audio data or video data, Parity Framesserving as data for error correction and Reporting Frames serving asother control data are outputted from Bluetooth AV device throughrespective stream end points, and are delivered to the above-describedAdaptation Layers provided in correspondence with respective stream endpoints. In the respective Adaptation Layers, as described above, mediaframes, parity frames and reporting frames are caused to be in a packetform. The streams caused to be in a packet form are delivered torespective logical link management layer channels, and are outputted tothe external through the above-described physical layer. Additionally,command and response are adapted so that links are separately givenalthough not shown, and are caused to undergo transmission/receptionthrough such links.

Now, more practical data transmission system to which Bluetoothspecification in which such protocol is prescribed is applied will bedescribed below.

First, as an example of data transmission system for carrying outcorrelating between interface with respect to stream within theequipment and interface with respect to stream between equipments, aplayback (reproduction) system 1 shown in FIG. 8 will be described. Inthis playback (reproduction) system 1, a player 10 with audio tuner anda headphone 20 that a remote controller 30 for carrying out remotecontrol of this player 10 is attached are connected by Bluetooth link.The player 10 becomes operative in accordance with instruction from theheadphone 20. The headphone 20 receives audio stream outputted from theplayer 10 and outputs such audio stream to the external as voice.

The playback (reproduction) system 1 comprises, as shown in FIG. 9, theplayer 10 serving as a first electronic equipment (other electronicequipment) which outputs audio stream generated by plural signalsources, and the headphone 20 serving as a second electronic equipmentwhich can carry out remote control of this player 10, and serves toreceive audio stream outputted from the player 10 to output such audiostream to the external as voice. These player 10 and headphone 20 arerespectively located as units which logically represent set ofphysically existing equipments.

The player 10 serves to reproduce audio data recorded at variousrecording media, and together has a function of audio tuner whichreceives audio data from the external. The player 10 includes a firstsignal generating unit 11 which is signal generating means serving assignal source of stream to perform primary function, i.e., to reproduceaudio data from the recording medium to thereby transmit the audio datato the external, a second signal generating unit 12 which is signalgenerating means serving as signal source of stream to receive audiodata as audio tuner to thereby transmit the audio data to the external,an interface unit 13 for carrying out transmission/reception of commandand response and transmission of audio streams generated by the firstsignal generating unit 11 and the second signal generating unit 12, anda system control unit 14 for controlling these respective units.

The first signal generating unit 11 serves to reproduce audio datarecorded with respect to various recording media, e.g., disc-shapedrecording medium such as CD (Compact Disc), DVD (Digital Versatile Disc)or MD (Mini Disc), etc. tape-shaped recording medium, and/or thin typesemiconductor memory caused to be in substantially plate form. Thisfirst signal generating unit 11 is a unit which is lower rank concept ofthe player 10 and is located as subunit representing set for realizinglogical function of equipment. The first signal generating unit 11reproduces audio data under control of the system control unit 14 tothereby function as signal source. The first signal generating unit 11delivers generated data to the interface unit 13.

The second signal generating unit 12 serves to receive audio data fromthe external as an audio tuner, such as, for example, radio set, etc.This second signal generating unit 12 is located as subunit similarly tothe first signal generating unit 11. The second signal generating unit12 receives audio data under control of the system control unit 14 tooutput the audio data to thereby function as signal source. The secondsignal generating unit 12 delivers generated data to the interface unit13.

The interface unit 13 receives command C transmitted from the headphone20 in accordance with protocol in the above-described Bluetoothspecification to deliver this command C to the system control unit 14.Moreover, the interface unit 13 transmits response R with respect to thecommand C generated by the system control unit 14 to the headphone 20,and transmits stream ST caused to be in a packet form delivered from thefirst signal generating unit 11 or the second signal generating unit 12to the headphone 20. Here, the interface unit 13 is provided with twoBluetooth output plugs 13 a, 13 b as the above-described plug so as tohave ability to output two signal sources, i.e., streams ST caused to bein a packet form delivered from the first signal generating unit 11 andthe second signal generating unit 12 to assign respective streams ST. Inthis example, it is assumed that Bluetooth output plug 13 a is assignedas interface with respect to stream within the equipment outputted fromthe first signal processing unit 11, and Bluetooth output plug 13 b isassigned as interface with respect to stream within the equipmentoutputted from the second signal generating unit 12.

The system control unit 14 analyses command C transmitted from theheadphone 20 and received by the interface unit 13 to operate the firstsignal generating unit 11 or the second signal generating unit 12 inaccordance with this command C, and generates response R with respect tothe command C to deliver the response R to the interface unit 13.

Such player 10 operates in accordance with command C transmitted fromthe headphone 20. In the case where the command C is command indicatingthat audio data recorded with respect to the recording medium isreproduced, the player 10 operates the first signal generating unit 11under control of the system control unit 14. In the case where thecommand C is command indicating that audio data is received by thetuner, the player 10 operates the second signal generating unit 12 undercontrol of the system control unit 14. Here, the player 10 is providedwith Bluetooth output plugs 13 a, 13 b respectively corresponding to thefirst signal generating unit II and the second signal generating unit 12to cause these plugs to be interface with respect to stream within theequipment.

Namely, in the playback (reproduction) system 1, as shown in FIG. 10,the AV/C unit model is extended to newly prescribe, as plugs used fordata transmission by general bus including Bluetooth, 31 General BusInput Plugs and 31 General Bus Output Plugs in addition to Serial BusIsochronous Input Plugs, Serial Bus Isochronous Output Plugs, Serial BusAsynchronous Input Plugs, Serial Bus Asynchronous Output Plugs, ExternalInput Plugs, and External Output Plugs which have been alreadyprescribed in the AV/C unit model.

In more practical sense, as shown in the following Table 1, addressesare assigned to these plugs. Thus, plug numbers are discriminated.Additionally, “16” of the bottom attached character in theabove-mentioned Table indicates that addresses are described byhexadecimal number. Namely, in the playback (reproduction) system 1,partial address values CO₁₆-DF₁₆ of unused address values CO₁₆-FC₁₆which are caused to be reserved address for expansion of addresses whichare already prescribed as unit plug in the AV/C are newly prescribed as31 General Bus input/output plugs used in general bus includingBluetooth, and these General Bus input/output plugs are used asBluetooth input/output plugs. In the player 10, predetermined twoaddress values are assigned as Bluetooth output plugs 13 a, 13 b amongthese 31 General Bus output plugs. In the player 10, these Bluetoothoutput plugs 13 a, 13 b and the first and second signal generating units11 and 12 are respectively connected fixedly or after suitably undergoneswitching, whereby transmission path of stream within the player 10 isestablished.

TABLE 1 Value Unit Input Plug Unit Output Plug 00₁₆-1E₁₆ Serial BusInput Plug 0-30 Serial Bus Output Plug 0-30 (iPCR 0-30) (oPCR 0-30)1F₁₆-7E₁₆ Reserved Reserved 7F₁₆ Any available Any available Serial BusInput Plug Serial Bus Output Plug 80₁₆-9E₁₆ External Input Plug 0-30External Output Plug 0-30 9F₁₆ Reserved Reserved A0₁₆-BE₁₆ Serial BusAsynchronous Serial Bus Asynchronous Input Plug 0-30 Output Plug 0-30BF₁₆ Any available Any available Serial Bus Asynchronous Serial BusAsynchronous Input Plug Output Plug C0₁₆-DE₁₆ General Bus Input PlugGeneral Bus Output Plug 0-30 0-30 DF₁₆ Any available General Bus Anyavailable General Bus Input Plug Output Plug E0₁₆-FC₁ Reserved ReservedFD₁₆ Reserved Multiple Plug FE₁₆ Invalid Invalid FF₁₆ Any available Anyavailable External Input Plug External Output Plug

On the other hand, as described above, the headphone 20 additionallyincludes a remote controller 30 for carrying out remote control of theplayer 10, and functions as an external output equipment which receivesaudio stream outputted from the player 10 to output it as voice. Theheadphone 20 includes an interface unit 21 for carrying outtransmission/reception of command and response and/or reception of audiostream transmitted from the player 10, a signal processing unit 22 forprocessing received audio stream, a system control unit 23 serving ascommand generating means and response analysing means for controllingrespective units, and a display unit 24 for displaying variousinformation.

The interface unit 21 receives stream ST transmitted from the player 10in accordance with protocol in the above-described Bluetooth to deliverthis stream to the signal processing unit 22. Moreover, the interfaceunit 21 transmits command C generated by the system control unit 23 tothe player 10, and receives response R with respect to the command Ctransmitted from the player 10 to deliver the response R to the systemcontrol unit 23.

The signal processing unit 22 implements a predetermined processing tostream delivered from the interface unit 21 under control of the systemcontrol unit 23 to output it from speaker (not shown) to the external asvoice.

The system control unit 23 generates command C to deliver it to theinterface unit 21. Moreover, the system control unit 23 analysesresponse R transmitted from the player 10 and received by the interfaceunit 21 to operate the signal processing unit 22 in accordance with thisresponse R, and generates information for allowing display unit 24 whichwill be described later to carry out display.

The display unit 24 displays information indicating signal source on thebasis of information delivered from the system control unit 23. Forexample, the display unit 24 is operative so that in the case where theoperating state of the player 10 is such that audio data is reproducedby the first signal generating unit 11, it displays information of “discplayback”, and in the state where the operating state of the player 10is such that audio data is received by the second signal generating unit12, it displays information of “tuner receiving”.

Such headphone 20 carries out setup of connection to and from the player20 as the above-described initiator, and transmits command C by theremote controller 30 when connection is established. Further, theheadphone 20 receives stream ST transmitted from the player 10 to outputit as voice to the external. In addition, the headphone 20 receivesresponse R transmitted from the player 10 in accordance with command Ctransmitted by the remote controller 30 to carry out processingcorresponding to this response R.

Meanwhile, in such playback system 1, the headphone 20 can grasp SEIDwith respect to receiving stream ST in the process where connection byAVDTP is established between the headphone 20 and the player 10 asdescribed later. Moreover, as described later, the headphone 20transmits command for inquiring internal connection by AVCTP to theplayer 10, thereby also making it possible to grasp subunit to whichBluetooth output plug 13 a or 13 b is connected, i.e., either the firstsignal generating unit 11 or the second signal generating unit 12 towhich Bluetooth output plug 13 a or 13 b is connected. For this reason,if the headphone 20 can grasp the relationship between SEID andBluetooth output plug No., it can display information of signal source,e.g., the above-described “disc playback” or “tuner receiving” on thedisplay unit 24.

In view of the above, in the playback system 1, command for inquiringmapping of SEID and Bluetooth output plug No. and response thereof arenewly prescribed to carry out correlating between SEID and Bluetoothoutput plug No. by using the inquiry command and the response. In thisexample, inquiry commands and responses by four kinds of definitions arenewly proposed.

First, the inquiry command and the response by the first definition willbe described. The inquiry command and the response by the firstdefinition are realized by incorporation newly carried out into regularAV/C command and AV/C response.

Command frame of inquiry command for inquiring information relating toinput plug is constituted as shown in FIG. 11. Namely, this commandframe is such that “0000” indicating “AV/C” is stored as commandtransaction set field (Command Transaction Set; cts), “status”indicating command for inquiring status of equipment is stored ascommand type field (Command type; ctype), and information foridentifying unit to be inquired is stored in the state designated as“unit” as subunit type field (subunit_type) and subunit ID field(subunit_ID).

Moreover, this command frame is caused to be of configuration in whichopcode field (opcode) is stored in the state where informationindicating command for inquiring information relating to input plug isdesignated as “Setup Network Input Plug”, 0-th operand field (Operand[0]) is used as input plug No. field (input_plug) indicating input plugNo., the first operand field (Operand [1]) is used as network type field(network_type) indicating kind of network, the second operand field(Operand [2]) is used as length field (length) indicating length ofinformation indicated in the third operand field (Operand [3]) andoperand fields succeeding thereto, and the third operand field (Operand[3]) to the n-th operand field (Operand [n]) are used as network typedependent field (network_type_dependent) indicating information foridentifying interface with respect to stream between equipments likeSEID.

In this example, network type dependent field (network_type_dependent)is caused to be adjustable in order to cope with various networksincluding Bluetooth. If corresponding area is area from the thirdoperand field (Operand [3]) to the n-th operand field (Operand [n]),field of arbitrary length can be used.

On the other hand, response frame with respect to such inquiry commandis constituted as shown in FIG. 12. Namely, this response frame is suchthat “0000” indicating “AV/C” is stored as command transaction set field(Command Transaction Set; cts), “stable” indicating that equipment isstable is stored as response code field (Response code; response), andinformation for identifying inquired unit is stored in the statedesignated as “unit” as subunit type field (subunit_type) and subunit IDfield (subunit_ID).

Moreover, this response frame is caused to be of the configuration inwhich opcode field (opcode) is stored in the state designated as “SetupNetwork Input Plug”, the 0-th operand field (Operand [0]) is used asinput plug No. field (input_plug), the first operand field (Operand [1])is used as network type field (network_type), the second operand field(Operand [2]) is used as length field (length), and the third operandfield (Operand [3]) to the n-th operand field (Operand [n]) are used asnetwork type dependent field (network_type_dependent).

Command frame of inquiry command for inquiring information relating tooutput plug is constituted as shown in FIG. 13. Namely, this commandframe is caused to be similar to the command frame of which fundamentalconfiguration is shown in FIG. 11, and is caused to be of theconfiguration in which opcode field (opcode) is stored in the statewhere information indicating command for inquiring information relatingto output plug is stored in the state designated as “Setup NetworkOutput Plug”, and the 0-th operand field (Operand [0]) is used as outputplug No. field (Output_plug) indicating output plug No.

On the other hand, response frame with respect to such inquiry commandis constituted as shown in FIG. 14. Namely, this response frame iscaused to be the same as the response frame of which fundamentalconfiguration is shown in FIG. 12, and is caused to be of theconfiguration in which opcode field (opcode) is stored in the statedesignated as “Setup Network Output Plug”, and the 0-th operand field(Operand [0]) is used as output plug No. field (Output_plug).

As described above, inquiry command and response by the first definitionare adapted so that incorporation into regular AV/C command and AV/Cresponse is newly carried out to thereby eliminate the possibility thatthere result command and response peculiar to general buss includingBluetooth, thus making it possible to follow control by the regular AV/Ccommand and AV/C response.

In order to give explanation in more practical sense, inquiry commandfor inquiring mapping of SEID and Bluetooth output plug No. and responsethereof are taken as an example.

As a first example of the first definition, explanation will be given inconnection with the case where an equipment serving as controller likethe headphone 20 in the playback (reproduction) system 1 grasps SEID inthe equipment serving as target like the player 10, and inquiresBluetooth output plug No. corresponding to this SEID.

In this case, command frame is caused to be of the configuration inwhich, e.g., information as shown in FIG. 15 is stored. Namely, thecommand frame is caused to be of the configuration in which opcode field(opcode) is caused to be “Setup Network Output Plug”, the 0-th operandfield (Operand [0]) used as output plug No. field (Output plug) iscaused to be “FF” in order to demand answer to inquiry, the firstoperand field (Operand [1]) used as network type field (network_type) iscaused to be “01₁₆” indicating “Bluetooth Network”, the second operandfield (Operand [2]) used as length field (length) is caused to be value“01₁₆” indicating 1 byte, and the third operand field (Operand [3]) usedas network type dependent field (network_type_dependent) is caused to bevalue “12₁₆” indicating grasped “SEID”. Additionally, fields from thefourth operand field (Operand [4]) to the n-th operand field (Operand[n]) are not used because value “01₁₆” indicating 1 byte is stored atlength field (length), and command frame is caused to be of theconfiguration in which value “12₁₆” indicating “SEID” is stored at thethird operand field (Operand [3]) consisting of 1 byte.

On the other hand, response frame is caused to be of the configurationin which, e.g., information as shown in FIG. 16 is stored. Namely, theresponse frame is caused to be of the configuration in which the 0-thoperand field (Operand [0]) used as output plug No. field (Output_plug)is caused to be value “C1₁₆” indicating “General Bus” as response toinquiry. Here, general bus output plug is plug which has been alreadyexplained by using FIG. 10, and the value “C1 ₁₆” is address defined inthe Table 1.

In the case where the equipment serving as controller grasps SEID in amanner as stated above, it generates command in which value of outputplug No. field (Output_plug) is caused to be “FF” to transmit thiscommand to the target equipment. Further, the target equipment generatesresponse in which Bluetooth output plug No. corresponding to SEID isstored as output plug No. field (Output_plug) to transmit this responseto the equipment serving as controller. For example, in the playback(reproduction) system 1, the headphone 20 generates command C totransmit it to the player 10, and the player 10 generates response R totransmit it to the headphone 20. Thus, the headphone 20 can grasp therelationship between this SEID and Bluetooth output plug No. on thebasis of the grasped SEID.

Subsequently, as a second example in the first definition, explanationwill be given in connection with the case where an equipment serving ascontroller like the headphone 20 in the playback (reproduction) system 1grasps general bus output plug No. in the equipment serving as targetlike the player 10, and inquires information for identifying interfacewith respect to stream between equipments corresponding to this generalbus output plug No.

In this case, command frame is caused to be of the configuration inwhich, e.g., information as shown in FIG. 17 is stored. Namely, thecommand frame is caused to be of the configuration in which opcode field(opcode) is caused to be “Setup Network Output Plug”, the 0-th operandfield (Operand [0]) used as output plug No. field (Output_plug) iscaused to be value “C1₁₆” indicating grasped “General Bus”, the firstoperand field (Operand [1]) used as network type field (network_type)and the second operand field (Operand [2]) used as length field (length)are cause to be “FF” in order to demand answer to inquiry. Additionally,fields from the third operand field (Operand [3]) to the n-th operandfield (Operand [n]) are not used. In addition, the reason why networktype field (network_type) and length field (length) are caused to be“FF” is that it is impossible to grasp kind of network at the stagewhere equipment serving as controller grasps only information of outputplug, and cannot also grasp, followed by this, information foridentifying interface with respect to stream between equipments storedat fields succeeding to the third operand field (Operand [3]) asresponse.

On the other band, response frame is caused to be of the configurationin which, e.g., information as shown in FIG. 18 is stored. Namely, theresponse frame is caused to be of the configuration in which the firstoperand field (Operand [1]) used as network type field (network_type) iscaused to be value “01₁₆” indicating “Bluetooth” as response to inquiry,the second operand field (Operand [2]) used as length field (length) iscaused to be value “01₁₆” indicating 1 byte as answer to inquiry, andthe third operand field (Operand [3]) used as network type dependentfield (network_type_dependent) is caused to be value “12₁₆” indicating“SEID”. Additionally, fields from the fourth operand field (Operand [4])to the n-th operand field (Operand [n]) are not used because value“01₁₆” indicating 1 byte is stored at length field (length), and theresponse frame is caused to be of the configuration in which value“12₁₆” indicating “SEID” is stored at the third operand field (Operand[3]) consisting of 1 byte.

In the case where an equipment serving as controller grasps general busoutput plug No. in a manner as stated above, it generates command inwhich values of network type field (network_type) and length field(length) are caused to be “FF” to transmit this command to the targetequipment. Further, the target equipment generates response in whichinformation indicating kind of network used for transmission of streamis stored as network type field (network_type), information indicatinglength of information for identifying interface with respect to streambetween equipments is stored as length field (length), and informationfor identifying interface corresponding to general bus output plug No.is stored as network type dependent field (network_type dependent) totransmit this response to an equipment serving as controller. Forexample, in the playback (reproduction) system 1, the headphone 20generates command C to transmit it to the player 10 and the player 10generates response R to transmit it to the headphone 20. Thus, theheadphone 20 can grasp the relationship between grasped general busoutput plug No. and information for identifying interface.

Subsequently, inquiry command and response by the second definition willbe described. Command frame of inquiry command for inquiring informationrelating to input plug is constituted as shown in FIG. 19. Namely, thiscommand frame is such that “0000” indicating “AV/C” is stored as commandtransaction set field (Command Transaction Set; cts), “status”indicating command for inquiring status of equipment is stored ascommand type field (Command type; ctype), and information foridentifying unit to be inquired is stored in the state designated as“unit” as subunit type field (subunit_type) and subunit ID field(subunit_ID).

Moreover, this command frame is caused to be of the configuration inwhich opcode field (opcode) is stored in the state where informationindicating command for inquiring information relating to input plug isdesignated as “General Bus Setup”, the 0-th operand field (Operand [0])is used as bus type field (bus_type) indicating kind of network, and thefirst field operand field (Operand [1]) to the n-th operand field(Operand [n]) are used as bus type dependent field (bus_type_dependent)indicating correspondence with information for identifying interfacewith respect to steam between equipments like General Bus Plug and SEID.

Here, with respect to bus type dependent field (bus_type_dependent),field length and data configuration are defined every bus in order tocope with various buses including Bluetooth network.

On the other hand, response frame with respect to such inquiry commandis constituted as shown in FIG. 20. Namely, this response frame is suchthat “0000” indicating “AV/C” is stored as command transaction setfield(Command Transaction Set; cts), “stable” indicating that equipment isstable is stored as response code field (Response code; response), andinformation for identifying inquired unit is stored in the statedesignated as “unit” as subunit type field (subunit_type) and subunit IDfield (subunit_ID).

Further, this response frame is caused to be of the configuration inwhich opcode field (opcode) is stored in the state designated as“General Bus Setup”, the 0-th operand field (Operand [0]) is used as bustype field (bus_type), and the first operand field (Operand [1]) to then-th operand field (Operand [n]) are used as bus type dependent field(bus_type_dependent).

As stated above, the inquiry command and the response by the seconddefinition are adapted so that incorporation into regular AV/C commandand AV/C response is newly carried out to eliminate the possibility thatthere result command and response peculiar to general buss includingBluetooth, thus making it possible to follow control by the regular AV/Ccommand and AV/C response.

In order to give explanation in more practical sense, inquiry commandfor inquiring mapping of SEID and Bluetooth output plug No. and responsethereof are taken as an example.

As a first example in the second definition, explanation will be givenin connection with the case where an equipment serving as controllerlike the headphone 20 in the playback (reproduction) system 1 graspsSEID in the target equipment like the player 10, and inquires Bluetoothoutput plug No. corresponding to this SEID.

In this case, command frame is caused to be of the configuration inwhich, e.g., information as shown in FIG. 21 is stored. Namely, thecommand frame is such that opcode field (opcode) is caused to be“General Bus Setup”, and the 0-th operand field (Operand [0]) used asbus type field (bus_type) is caused to be value “40₁₆” indicating“Bluetooth network” and is used as bus type dependent field(bus_type_dependent). At the first operand field (Operand [1]), it isdesignated that corresponding plug is Output Plug. The second operandfield (Operand [2]) is caused to be “FF₁₆” in order to demand answer toinquiry. In addition, the third operand field (Operand [3]) is caused tobe value “12₁₆” indicating grasped “SEID”.

On the other hand, response frame is caused to be of the configurationin which, e.g., information as shown in FIG. 22 is stored. Namely, theresponse frame is caused to be of the configuration in which the secondoperand field (Operand [2]) used as plug No. field is caused to be value“C1₁₆” indicating “General Bus Plug” as answer to inquiry. Here, GeneralBus Output Plug is plug which has been already explained by using FIG.10, and the value “C₁ ₁₆” is address defined in the Table 1.

In the case where an equipment serving as controller grasps SEID in amanner stated above, it generates command in which value of plug No.field is caused to be “FF” to transmit this command to the targetequipment. Further, the target equipment generates response in whichBluetooth output plug No. corresponding to SEID is stored as plug No.field to transmit this response to the equipment serving as controller.For example, in the playback (reproduction) system 1, the headphone 20generates command C to transmit it to the player 10, and the player 10generates response R to transmit it to the headphone 20. Thus, theheadphone 20 can grasp the relationship between this SEID and Bluetoothoutput plug No. on the basis of the grasped SEID.

Subsequently, as a second example in the second definition, explanationwill be given in connection with the case where an equipment serving ascontroller like the headphone 20 in the playback system 1 grasps generalbus output plug No. in the target equipment like the player 10, andinquires information for identifying interface with respect to streambetween equipments corresponding to this general bus output plug No.

In this case, command frame is caused to be of configuration in which,e.g., information as shown in FIG. 23 is stored. Namely, the commandframe is caused to be of the configuration in which opcode field(opcode) is caused to be “General Bus Setup”, the 0-th operand field(Operand [0]) used as bus type field (bus_type) is caused to be value“40₁₆” indicating “Bluetooth”, Output is designated by the first operandfield (Operand [1]) used as input/output plug (Input/Output)designation, the second operand field (Operand [2]) used as plug No. iscaused to be value “C1₁₆” indicating General Bus Plug #1, and the thirdoperand field (Operand [3]) is caused to be “FF₁₆” in order to demandanswer to inquiry.

On the other band, response frame is caused to be of the configurationin which, e.g., information as shown in FIG. 22 is stored. Namely, theresponse frame is caused to be of the configuration in which the thirdoperand field (Operand [3]) is caused to be value “12₁₆” indicating“SEID”.

In the case where the equipment serving as controller grasps General Businput/output plug No. in a manner stated above, it generates command inwhich value of field indicating stream end point of each bus defined bybus type dependent field (bus_type_dependent) is caused to be “FF” totransmit this command to the target equipment. Further, the targetequipment generates response in which information for identifyinginterface corresponding to General Bus input/output plug No. is storedto transmit this response to the equipment serving as controller. Forexample, in the playback (reproduction) system 1, the headphone 20generates command C to transmit it to the player 10, and the player 10generates response R to transmit it to the headphone 20. Thus, theheadphone 20 can grasp the relationship between grasped general busoutput plug No. and information for identifying interface.

Subsequently, inquiry command and response by the third definition willbe described. The inquiry command and response by the third definitionis such that AV/C command is extended to define another command set tocarry out definition as command peculiar to Bluetooth network.

Command frame of inquiry command is constituted as shown in FIG. 24.Namely, this command frame is such that “0000” indicating “AV/C” isstored as command transaction set field (Command Transaction Set; cts),“status” indicating command for inquiring status of equipment is storedas command type field (Command type; ctype), information for identifyingunit to be inquired is stored in the state designated as “unit” assubunit type field (subunit_type) and subunit ID field (subunit_ID), andopcode field (opcode) is stored in the state where informationindicating vender dependent command is designated as “VENDER·DEPENDENT”.

Moreover, operand field (Operand [0]·Operand [n]) is roughly classifiedinto company ID field (company_ID) and vender dependent data field(Vender dependent data). As the company ID field (company_ID), fieldsfrom the 0-th operand field (Operand [0]) to the second operand field(Operand [2]) are used. At the company ID field (company_ID), valuesindicating inherent identification information for “Bluetooth SIG” arestored.

Further, format of vender dependent data field (Vender dependent data)can be arbitrarily specified by vender, and is used here in the stateroughly classified into category field (category), function type field(function type), and function type dependent data field (function typedependent data). At the category field (category), informationindicating inquiry of interface in any protocol is stored. In the casewhere Bluetooth input/output plug is inquired, value indicating “AVCTP”is stored. At function type field (function type), informationindicating kind of command is stored, and value indicating “plugmapping” is stored.

Furthermore, the function type dependent data field (function typedependent data) is roughly classsified into Bluetooth input/output plugNo. field (Bluetooth plug #) and SEID field (SEID), and either one valueamong them is stored as “FF”. Namely, in the case where SEID is graspedand Bluetooth input/output plug No. corresponding to this SEID isdesired to be obtained, “FF” is stored in order to obtain answer toquestion as Bluetooth input/output plug No. field (Bluetooth plug #) andvalue of grasped SEID is stored as SEID field (SEID) at function typedependent data field (function type dependent data). Moreover, in thecase where Bluetooth input/output plug No. is grasped and SEIDcorresponding to this Bluetooth input/output plug No. is desired to beobtained, value of grasped Bluetooth input/output plug No. is stored asBluetooth input/output plug No. field (Bluetooth plug #) and “FF” isstored in order to obtain answer to question as SEID field (SEID) atfunction type dependent data field (function type dependent data). Inthis case, Bluetooth input/output plug belongs to General Businput/output plug which has been already explained by using FIG. 10.

On the other hand, response frame is caused to be of the configurationin which, e.g., information as shown in FIG. 25 is stored. Namely, theresponse frame is caused to be of the configuration in which, in thecase of response corresponding to command for inquiring Bluetoothinput/output plug No. as in the command shown in FIG. 24, Bluetoothinput/output plug No. field (Bluetooth plug #) is caused to be valueindicating Bluetooth input/output plug No. corresponding to SEID storedin SEID field (SEID) as answer to inquiry. Moreover, the response frameis caused to be of the configuration in which, in the case of responsecorresponding to command for inquiring SEID, SEID field (SEID) is causedto be value indicating SEID corresponding to Bluetooth input/output plugNo. stored in Bluetooth input/output plug No. field (Bluetooth plug #)as answer to inquiry.

As stated above, inquiry command and response by the third definitioncan be defined as command peculiar to Bluetooth application by usingvender dependent command (VENDER-DEPENDENT). An equipment serving ascontroller generates command in which value of either one of Bluetoothinput/output plug No. field (Bluetooth plug #) and SEID field (SEID) iscaused to be “FF” to transmit this command to the target equipment.Further, the target equipment generates response in which SEID orBluetooth input/output plug No. is stored as Bluetooth input/output plugNo. field (Bluetooth plug or SEID field (SEID) to transmit this responseto the equipment serving as controller. For example, in the playback(reproduction) system 1, the headphone 20 generates command C totransmit it to the player 10, and the player 10 generates response R totransmit it to the headphone 20. Thus, the headphone 20 can grasp therelationship between SEID and Bluetooth output plug No. on the basis ofgrasped SEID or Bluetooth input/output plug No.

Subsequently, inquiry command and response by the fourth definition willbe described. In the inquiry command and response by the fourthdefinition, AV/C command is extended to define another command set todefine it as command peculiar to Bluetooth application.

The command frame of the inquiry command is constituted as shown in FIG.26. Namely, this command frame is such that value except for “0000”indicating extended command except for “AV/C” is stored as commandtransaction set field (Command Transaction Set; cts). Here, forconvenience, such value is assumed to be “Extended AV/C”. Moreover, thecommand frame is such that “status” indicating command for inquiringstatus of equipment is stored as command type field (Command type;ctype), information for identifying unit to be inquired is stored in thestate designated as “unit” as subunit type field (subunit_type) andsubunit ID field (subunit_ID), and information indicating plug mappingcommand is stored at the opcode field (opcode) in the state designatedas “Bluetooth Plug Mapping”.

Further, the operand field (Operand [0]·Operand [n]) is roughlyclassified into Bluetooth input/output plug No. field (Bluetooth plug #)and SEID field (SEID), and either one of value among them is stored as“FF”. Namely, in the case where SEID is grasped and Bluetoothinput/output plug No. corresponding to this SEID is desired to beobtained, “FF” is stored in order to obtain answer to inquiry asBluetooth input/output plug No. field (Bluetooth plug #), and value ofgrasped SEID is stored as SEID field (SEID). In addition, in the casewhere Bluetooth input/output plug No. is grasped and SEID correspondingto this Bluetooth input/output plug No. is desired to be obtained, valueof grasped Bluetooth input/output plug No. is stored as Bluetoothinput/output plug No field (Bluetooth plug #), and “FF” is stored inorder to obtain answer to inquiry as SEID field (SEID). In this case,Bluetooth input/output plug belongs to general bus input/output plugwhich has been already explained by using FIG. 10.

On the other hand, response frame is caused to be of the configurationin which, e.g., information as shown in FIG. 27 is stored. Namely, theresponse frame is caused to be of the configuration in which, in thecase of response corresponding to command for inquiring Bluetoothinput/output plug No. as in the command shown in FIG. 26, Bluetoothinput/output plug No. field (Bluetooth plug #) is caused to be valueindicating Bluetooth input/output plug No. corresponding to SEID storedin SEID field (SEID) as answer to inquiry. In addition, the responseframe is caused to be of the configuration in which, in the case ofresponse corresponding to command for inquiring SEID, SEID field (SEID)is caused to be value indicating SEID corresponding to Bluetoothinput/output plug No. stored in Bluetooth input/output plug No. field(Bluetooth plug #).

As stated above, in the inquiry command and the response by the fourthdefinition, AV/C command is extended to define another command set,thereby making it possible to define it as command peculiar to Bluetoothapplication. An equipment serving as controller generates command inwhich either one value of Bluetooth input/output plug No. field(Bluetooth plug #) and SEID field (SEID) is caused to be “FF” totransmit this command to the target equipment. Further, the targetequipment generates response in which SEID or Bluetooth input/outputplug No. is stored as Bluetooth input/output plug No. field (Bluetoothplug #) or SEID field (SEID) to transmit this response to the equipmentserving as controller. For example, in the playback (reproduction)system 1, the headphone 20 generates command C to transmit it to theplayer 10, and the player 10 generates response R to transmit it to theheadphone 20. Thus, the headphone 20 can grasp the relationship betweenSEID and Bluetooth output plug No. on the basis of grasped SEID orBluetooth input/output plug No.

Meanwhile, in the playback system 1, such inquiry commands and responsesby four kinds of definitions are used to carry out a series ofprocessing as shown in FIG. 28 to thereby carry out correlating betweenBluetooth input/output plug No. for identifying Bluetooth input/outputplug which is interface with respect to steam within the equipment andSEID for identifying stream end point which is interface with respect tostream between equipments, thus making it possible to obtain informationof signal source of stream at the receiving side.

First, in the playback system 1, as shown in the figure, at step S1,connection by AVDTP is established between the headphone 20 serving ascontroller and the player 10 serving as target by the headphone 20 tothereby grasp SEID with respect to receiving stream.

In more practical sense, the headphone 20 transmits command ofsignalling to receive response thereof to thereby grasp SEID withrespect to receiving stream in the process where connection isestablished. In order to establish connection between the headphone 20and the player 10, the headphone 20 first collects “Service_Overview” ofthe player 10 by using command of “Stream_Info_Overview” which is one ofcommands of signalling. Subsequently, the headphone 20 selects SEIDthereafter to collect “Service_Capability” of SEID by using command of“Stream_Info” which is one of commands of signalling. Further, theheadphone 20 selects “Capability” of SEID by using command of“Set_Configuration” which is one of commands of signalling.

In this way, the headphone 20 can establish connection between theheadphone 20 and the player 10, and can grasp SEID in that process.

Subsequently, in the playback system 1, at step S2, either one ofinquiry commands by the above-described three kinds of definitions isused to designate SEID by the headphone 20 to inquire correspondingBluetooth output plug No.

Namely, the headphone 20 transmits the inquiry command which has beenalready shown in FIG. 15, FIG. 24 or FIG. 26 to the player 10 to therebyinquire Bluetooth output plug No. The headphone 20 receives responsetransmitted from the player 10 to analyse the received response, therebymaking it possible to grasp Bluetooth output plug No. corresponding todesignated SEID.

Subsequently, in the playback system 1, at step S3, grasped Bluetoothoutput plug No. is designated by the headphone 20 to inquire connectingdestination within the player 10 of this Bluetooth output plug.

Namely, the headphone 20 designates Bluetooth output plug to inquirewhether stream outputted from this Bluetooth output plug uses eithersubunit of the first signal generating unit 11 or the second signalgenerating unit 12 as signal source. For example, the headphone 20transmits, to the player 10, connect command (CONNECT command) forexamining correspondence relationship between source plug No.(source_plug) and destination plug No. (destination_plug) as commandframe is shown in FIG. 29, thereby making it possible to inquireconnecting destination within the player 10 of Bluetooth output plug. Inthis case, in CONNECT command, although not shown, “status” indicatingcommand for inquiring status of equipment is stored as command typefield (Command type; ctype). The headphone 20 receives responsetransmitted from the player 10 to analyse the response, thereby makingit possible to grasp connecting destination within the player 10 ofBluetooth output plug.

Subsequently, in the playback system 1, at step S4 in FIG. 28, theoperating status of subunit serving as signal source is inquired by theheadphone 20.

Namely, the headphone 20 transmits existing AV/C command for inquiringoperating state of subunit to the player 10 to thereby inquire operatingstate of subunit serving as signal source. Here, as the operating stateof the first signal generating unit 11, there is operating state of“disc playback”, and as the operating of the second signal generatingunit 12, there is operating state of “tuner receiving”. The headphone 20receives and analyses response transmitted from the player 10, therebymaking it possible to grasp the operating state of subunit serving assignal source.

Further, in the playback system 1, at step S5, information indicatingsignal source of stream is displayed on the display unit 24 by theheadphone 20. Thus, a series of processing are completed.

In the playback system 1, such a series of processing go through tothereby carry out correlating between Bluetooth input/output plug No.for identifying Bluetooth input/output plug serving as interface withrespect to stream within the equipment and SEID for identifying streamend point serving as interface with respect to stream betweenequipments, thus making it possible to obtain information of signalsource of stream at the receiving side.

It is to be noted that while a series of processing shown in the figureare indicated in connection with the case where corresponding Bluetoothinput/output plug No. is inquired on the basis of SEID, it is a matterof course in the playback system 1 that it is possible to inquirecorresponding SEID on the basis of Bluetooth input/output plug No.

As stated above, in the playback system 1, even in the case where pluralsubunits are caused to serve as signal source like the player 10, theheadphone 20 can recognize signal source from which received stream isoutputted. Accordingly, the playback system 1 displays information ofsignal source on the display unit 24 by the headphone 20 to permit userto notice it so that control of the entirety of the playback system 1can be carried out. Thus, it is possible to provide high convenience foruser.

Subsequently, as an example of a data transmission system which is thesystem proposed at the opening sentence as more practical datatransmission system to which Bluetooth is applied, and in which whentransmission/reception of stream by Bluetooth is carried out between twoequipments, an equipment except for the two equipments is caused to becontroller to have ability to control connection between two equipmentsby this controller, a data transmission system 51 shown in FIG. 30 willbe described.

As shown in this figure, this data transmission system 51 serves tocarry out transmission/reception of stream ST such as audio stream orvideo stream, etc. by Bluetooth between a first device 60 and a seconddevice 70 serving as AV equipment. These first and second devices 60 and70 respectively correspond to the player 10 and the headphone 20 in theabove-described playback system 1. It is to be noted that the seconddevice 70 is not a device provided with a controller like the remotecontroller 30, but is a device which simply receives stream STtransmitted from the first device 60 to process it. In the datatransmission system 51, there is used, as a controller, a third device80 which is a device different from the first device 60 and the seconddevice 70, and is capable of carrying out transmission/reception of databy Bluetooth between the third device 80 and the first device 60. In thedata transmission system 51, it is possible to transmit command Cgenerated by command generating means (not shown) in the third device 80to the first device 60. In accordance with this, it is possible totransmit response R from the first device 60 to the third device 80.

Meanwhile, in such data transmission system 51, the first device 60 andthe second device 70 can establish connection by AVDTP between these twoequipments similarly to the above-described player 10 and headphone 20.For this reason, ordinarily the third device 80 cannot grasp connectionbetween these first and second devices 60 and 70 by any means. However,in the data transmission system 51, if the third device 80 can graspconnection between these first and second devices 60 and 70, it becomespossible to unitarily control connection between these two equipments.

In view of the above, in the data transmission system 51, command fordiscovering device in which connection can be made with respect to thefirst device 60 by the third device 80 and its response are newlyprescribed, and command for establishing connection between the firstdevice 60 and the second device 70 by the third device 80 is newlyprescribed.

First, command for discovering device in which connection can be madewith respect to the first device 60 by the third device 80 and itsresponse will be described.

As such command, command having, e.g., command frame as shown in FIG. 31is conceivable. Namely, in this command frame, similarly to the inquirycommand by the fourth definition used in the above-described playbacksystem 1, AV/C command is extended to define another command set.

In the command frame, value except for “0000” indicating extendedcommand except for “AV/C” is stored as command transaction set field(Command Transaction Set; cts). In this example, for convenience, theextended command except for “AV/C” is caused to be “Extended AV/C”.Moreover, in the command frame, “status” indicating command forinquiring status of equipment is stored as command type field (Commandtype; ctype), information for identifying unit to be inquired is storedin the state designated as “unit” as subunit type field (subunit_type)and subunit ID field (subunit_ID), and information indicating commandfor discovering device in which connection can be made is stored in thestate designated as “Bluetooth Possible Connections” as opcode field(opcode) Further, value for obtaining information of Bluetooth Device IDwhich will be described below as response is stored as “FF” at operandfield (Operand [0]·Operand [n]).

On the other hand, response frame is caused to be of the configurationin which, e.g., information as shown in FIG. 32 is stored. Namely, theresponse frame is caused to be of the configuration in which operandfield (Operand [0]·Operand [n]) is caused to be value indicatingBluetooth Device ID for identifying device in which connection can bemade as answer to inquiry. It is to be noted that it is not necessaryfor response frame to store value indicating Bluetooth Device ID as alloperand fields (Operand[0]-Operand [n]), but an arbitrary number ofoperand fields may be used. Namely, operand fields may be used by thenumber of discovered devices as device in which connection can be made.

Here, in this figure, values stored in operand fields (Operand[0]-Operand [n]) are caused to be “Bluetooth Device ID/SDP info”. Thisis to clearly express that the first device 60 which has receivedcommand discovers device listed up as response by using Bluetooth SDP(Bluetooth Service Discovery Protocol) which is one of protocolsprescribed in Bluetooth specification. Namely, when the first device 60receives command from the third device 80, it discovers devicecorresponding to Bluetooth AV protocol and device in which offeredservice corresponds to the first device 60 of devices in whichconnection can be made by using Bluetooth SDP. In more practical sense,in the case where the first device 60 is a device which transmits audiostream on Bluetooth link, the first device 60 discovers device which canreceive audio stream of connection available devices which can handleBluetooth application by using Bluetooth SDP. It is to be noted that itis not necessarily required for the first device 60 to use BluetoothSDP, but it is a matter of course that there may be used any deviceadapted for realizing similar function, i.e., function to discoverconnection available device.

As stated above, with respect to command and response, AV/C command isextended to have ability to define another command set. The third device80 serving as controller generates command in which value of operandfield (Operand [0]·Operand[n]) is caused to be “FF” to transmit thiscommand to the first device 60. Further, the first device 60 generatesresponse in which value indicating Bluetooth Device ID for identifyingconnection available device is stored as operand field (Operand[0]·Operand [n]) to transmit this response to the third device 80serving as controller.

Subsequently, command for establishing connection between the firstdevice 60 and the second device 70 by the third device 80 will bedescribed.

As such command, e.g., command having command frame as shown in FIG. 33is conceivable. Namely, similarly to the inquiry command by the fourthdefinition used in the above-described playback system 1, this commandframe is such that AV/C command is extended to define another commandset.

The command frame is such that value except for “0000” indicatingextended command except for “AV/C” is stored as command transaction setfield (Command Transaction Set; cts). Here, for convenience, extendedcommand except for “AV/C” is caused to be “Extended AV/C”. Moreover, thecommand frame is such that “status” indicating command for inquiringstatus of equipment is stored as command type field (Command type;ctype), information for identifying unit to be inquired is stored in thestate designated as “unit” as subunit type field (subunit_type) andsubunit ID field (subunit_ID), and information indicating command whichestablishes connection by Bluetooth is stored in the state designated as“Make Bluetooth Connection” as opcode field (opcode). Further, operandfields (Operand [0]-Operand [n]) are caused to be value indicatingBluetooth Device ID for identifying one device that the third device 80has arbitrarily selected from devices listed up by the response whichhas been already shown in FIG. 32.

As stated above, in this command, AV/C command is extended to haveability to define another command set. The third device 80 serving ascontroller generates command in which value of operand field (Operand[0]·Operand [n]) is caused to be arbitrarily selected Bluetooth DeviceID to transmit this command to the first device 60. Further, the firstdevice 60 generates response with respect to this command to transmitthis response to the third device 80 serving as controller, and carriesout processing corresponding to the command.

Meanwhile, in the data transmission system 51, such command and responseare used to carry out a series of processing as shown in FIG. 34,thereby making it possible to control connection between these first andsecond devices 60 and 70 by the third device when transmission/receptionof stream by Bluetooth is carried out between the first device 60 andthe second device 70.

First, in the data transmission system 51, as shown in the figure, atstep S11, device in which connection can be made with respect to thefirst device 60 is discovered by using the command which has beenalready shown in FIG. 31 by the third device 80 serving as controller.Namely, the third device 80 transmits the command which has been alreadyshown in FIG. 31 to the first device 60.

Subsequently, in the data transmission system 51, at step S12, device inwhich connection can be made is discovered in accordance with commandfrom the third device 80 by the first device 60 to list up it togenerate the response which has been already shown in FIG. 32 totransmit this response to the third device 80. At this time, the firstdevice 60 discovers corresponding device by using Bluetooth SDP asdescribed above.

Subsequently, in the data transmission system 51, at step S13, devicecaused to be connected to the first device 60 is selected in accordancewith response from the first device 60 by the third device 80 to connectthe first device 60 and this device by using the command which has beenalready shown in FIG. 33. Namely, the third device 80 transmits thecommand which has been already shown in FIG. 33 to the first device 60.

Further, in the data transmission system 51, at step S14, connection byAVDTP is established between the first device 60 and device selected bythe third device 80, i.e., the second device 70 in this example by thefirst device 60. At this time, the first device 60 establishesconnection by signalling as has been explained at the step S1 in FIG.28. The first device 60 transmits information indicating result whenestablishment of connection is tried to the third device 80 as responseto complete a series of processing.

In the data transmission system 51, such a series of processing gothrough, thereby making it possible to control connection between thesefirst and second devices 60 and 70 by the third device 80 whentransmission/reception of stream on Bluetooth link is carried outbetween the first device 60 and the second device 70.

As stated above, the data transmission system 51 can control connectionbetween two equipments by equipment except for two equipments whichcarries out transmission/reception of stream. Accordingly, the datatransmission system 51 can unitarily control connection between twoequipments, and can provide high convenience for user.

It is to be noted that while it has been explained in the datatransmission system 50 that transmission/reception of command andresponse carried out between the first device 60 and the third device 80is carried out on Bluetooth link, connection between a first device 110and a second device 120 which carry out transmission/reception of streamST on Bluetooth link may be also controlled by a third device 130functioning as controller in the IEEE 1394 as in the case of a datatransmission system 101 shown in FIG. 35 because command and responseshown in FIGS. 31 to 33 are defined by extending AV/C. Namely, in thedata transmission system 101, the first device 110 and the third device130 are connected by serial bus in conformity with the IEEE 1394, andtransmission/reception of command C and response R is carried outthrough this serial bus. At this time, as command C and response R,command and response shown in FIGS. 31 to 33 may be used. Of course, inthis case, it is needless to say that the first device 110 is requiredto have both Bluetooth interface and the IEEE 1394 interface.

As explained above, in the playback system 1, correlating betweenBluetooth input/output plug No. for identifying Bluetooth input/outputplug serving as interface with respect to stream within the equipmentand SEID for identifying stream end point serving as interface withrespect to stream between equipments, thereby making it possible toobtain information of signal source of stream at the receiving side.Even in the case where plural subunits are caused to serve as signalsource, information of signal source is displayed, thereby making itpossible to notify that information to user. Thus, it is possible toprovide high convenience for user.

In addition, in the data transmission systems 51, 101, whentransmission/reception of Bluetooth stream is carried out between twoequipments is carried out, it is possible to unitarily controlconnection between two equipments by equipment except for these twoequipments. Thus, it is possible to provide high convenience for user.

It should be noted that this invention is not limited to theabove-described embodiments. While explanation has been given by usingplayer 10 with audio tuner as an equipment of the side which transmitsstream, e.g., in the above-described playback system 1, this inventioncan be also applied to any equipment functioning as signal source, andmay be applied to an equipment which transmits video stream, etc. Ofcourse, it is not necessary that an equipment of the side which receivesstream is headphone 20, and arbitrary equipment which can receive streamis conceivable.

Moreover, while it has been explained in the above-described embodimentsthat player 10 in the playback system 1 is an equipment having twosignal sources, this invention may be applied even to an equipmenthaving subunit serving one or plural signal sources.

Further, while it has been explained in the above-described embodimentsthat headphone 20 in the playback system 1 is utilized for the purposeof displaying information of obtained signal source, this invention canbe applied also to the case where information of signal source isutilized for processing except for display. For example, it is possibleto notify such information to user by voice.

Furthermore, while it has been described in the above-describedembodiments that third devices 80, 130 in the data transmission systems51, 101 respectively carry out transmission/reception of command andresponse between the third devices 80, 130 and the first devices 60,110, this invention can be applied even to the case where the thirddevices 80, 130 respectively control connection through the seconddevices 70, 120.

In addition, while it has been described in the above-describedembodiments that, as command and response used in the data transmissionsystems 51, 101, similarly to command and response by the fourthdefinition in the playback system 1, there may be used command andresponse obtained by extending AV/C command to define another commandset, this invention may use command and response in which a method ofdefining command and response by the first definition or the thirddefinition used in the playback system 1 is applied.

As stated above, it is needless to say that this invention can besuitably changed within the scope which does not depart from the gist.

INDUSTRIAL APPLICABILITY

The data transmission system according to this invention makes aninquiry with respect to the first electronic equipment about mapping ofone identifier which has been grasped and the other identifier which hasnot been grasped on the basis of the one identifier which has beengrasped by the second electronic equipment to carry out correlatingbetween the one identifier and the other identifier to thereby haveability to obtain information of signal source of stream at the secondelectronic equipment to permit user to notify information of signalsource. For this reason, it is possible to provide high convenience foruser.

Moreover, the data transmission method according to this invention makesan inquiry with respect to the first electronic equipment about mappingof one identifier which has been grasped and the other identifier whichhas not been grasped on the basis of the one identifier which has beengrasped by the second electronic equipment to carry out correlatingbetween the one identifier and the other identifier to thereby haveability to obtain information of signal source of stream at the secondelectronic equipment to permit user to notify information of signalsource. For this reason, it is possible to provide high convenience foruser.

Further, the data transmission system according to this inventionselects the second electronic equipment in accordance with the firstelectronic equipment by the third electronic equipment to instinct thefirst electronic equipment to connect to the second electronicequipment, thereby making it possible to unitarily control connectionbetween two electronic equipments by the electronic equipment of thethird person except for these two electronic equipments whentransmission/reception of stream is carried out between two electronicequipments. Thus, it is possible to provide high convenience for user.

Further, the electronic equipment according to this invention selectsthe second electronic equipment in accordance with the first electronicequipment to instruct the first electronic equipment to connect to thesecond electronic equipment, thereby making it possible to unitarilycontrol connection between these two electronic equipments whentransmission/reception of stream is carried out between two electronicequipments. Thus, it is possible to provide high convenience for user.

Further, the data transmission system according to this invention givesan instruction so as to discover an electronic equipment in whichconnection can be made with respect to the first electronic equipment bythe third electronic equipment, thereby making it possible to grasp anelectronic equipment in which connection can be made with respect to oneelectronic equipment by an electronic equipment of the third personexcept for these two electronic equipments when transmission/receptionof stream is carried out between two electronic equipments. As a result,it is possible to unitarily control connection between two electronicequipments by the electronic equipment of the third person. Thus, it ispossible to provide high convenience for user.

In addition, the data transmission method according to this inventiongives an instruction so as to discover an electronic equipment in whichconnection can be made with respect to the first electronic equipment bythe third electronic equipment, thereby making it possible to grasp anelectronic equipment in which connection can be made with respect to oneelectronic equipment by an electronic equipment of the third personexcept for these two electronic equipments when transmission/receptionof stream is carried out between two electronic equipments. As a result,it is possible to unitarily control connection between two electronicequipments by the electronic equipment of the third person. Thus, itbecomes possible to provide high convenience for user.

The electronic equipment according to this invention gives aninstruction so as to discover an electronic equipment in whichconnection can be made with respect to the first electronic equipment,thereby making it possible to grasp an electronic equipment in whichconnection can be made with respect to one electronic equipment whentransmission/reception of stream is carried out between two electronicequipments. As a result, it is possible to unitarily control connectionbetween two electronic equipments. Thus, it is possible to provide highconvenience for user.

1. A data transmission system adapted for carrying outtransmission/reception of a stream by one or more electronic equipments,the data transmission system comprising: a first electronic equipment,comprising more than one signal generators, for transmitting the stream;a second electronic equipment which is wireless-connected to the firstelectronic equipment and is capable of receiving the stream; and a thirdelectronic equipment for generating a command for selecting the secondelectronic equipment in accordance with the first electronic equipment,and instructing the first electronic equipment to connect to the secondelectronic equipment, wherein a plurality of identifiers with respect tothe stream are used in the first electronic equipment including a firstidentifier for identifying an interface with respect to the streamwithin the first electronic equipment, output from one of the signalgenerators, and a second identifier for identifying an interface withrespect to the stream between the first electronic equipment and thesecond electronic equipment for receiving the stream.
 2. The datatransmission system as set forth in claim 1, wherein the thirdelectronic equipment generates a command to discover one or moreelectronic equipment for connecting to the first electronic equipment.3. The data transmission system as set forth in claim 2, wherein thefirst electronic equipment discovers devices for connection inaccordance with a command from the third electronic equipment to listthe devices to generate a response indicating the devices forconnection, and wherein the third electronic equipment selects thesecond electronic equipment from the devices for which connection can bemade in accordance with the response.
 4. The data transmission system asset forth in claim 1, wherein the first electronic equipment establishesa connection to the second electronic equipment which is selected by thethird electronic equipment.
 5. The data transmission system as set forthin claim 1, wherein the stream is an audio stream and/or a video stream.6. The data transmission system as set forth in claim 1, wherein thefirst electronic equipment and the second electronic equipment arewireless-connected by a Bluetooth link.
 7. The data transmission systemas set forth in claim 6, wherein the first electronic equipment and thethird electronic equipment are wireless-connected by a Bluetooth link.8. The data transmission system as set forth in claim 6, wherein thefirst electronic equipment and the third electronic equipment areconnected by a serial bus in conformity with the IEEE
 1394. 9. The datatransmission method as set forth in claim 6, wherein the firstelectronic equipment and the third electronic equipment are connected bya serial bus in conformity with the IEEE
 1394. 10. A data transmissionmethod of carrying out transmission/reception of a stream by a pluralityof electronic equipments, the data transmission method comprising: acommand generation step of generating a command for selecting, by athird electronic equipment, a second electronic equipment which iswireless-connected to a first electronic equipment for transmitting thestream and is capable of receiving the stream in accordance with thefirst electronic equipment to instruct the first electronic equipment toconnect to the second electronic equipment, wherein the first electronicequipment comprises more than one signal generators, wherein a pluralityof identifiers with respect to the stream are used in the firstelectronic equipment including a first identifier for identifying aninterface with respect to the stream within the first electronicequipment, output from one of the signal generators, and a secondidentifier for identifying an interface with respect to the streambetween the first electronic equipment and the second electronicequipment for receiving the stream.
 11. The data transmission method asset forth in claim 10, further comprising: a second command generationstep of generating a command to discover one or more electronicequipment for connection to the first electronic equipment.
 12. The datatransmission method as set forth in claim 11, further comprising: aresponse generation step of discovering devices in which a connectioncan be made in accordance with a command from the third electronicequipment generated at the second command generation step by the firstelectronic equipment to list the devices to generate a responseindicating the devices for connection, wherein, at the commandgeneration step, the second electronic equipment is selected from thedevices for connection in accordance with the response by the thirdelectronic equipment.
 13. The data transmission method as set forth inclaim 10, further comprising: a connection establishment step ofestablishing a connection with respect to the second electronicequipment selected by the third electronic equipment at the commandgeneration step by the first electronic equipment.
 14. The datatransmission method as set forth in claim 10, wherein the stream is anaudio stream and/or a video stream.
 15. The data transmission method asset forth in claim 10, wherein the first electronic equipment and thesecond electronic equipment are wireless-connected by a Bluetooth link.16. The data transmission method as set forth in claim 15, wherein thefirst electronic equipment and the third electronic equipment arewireless-connected by a Bluetooth link.
 17. A data transmission systemadapted for carrying out transmission/reception of a stream by aplurality of electronic equipments, the data transmission systemcomprising: a first electronic equipment for transmitting the stream; asecond electronic equipment which is wireless-connected to the firstelectronic equipment and is capable of receiving the stream; and a thirdelectronic equipment for generating a command to discover an electronicequipment or equipments in which connection can be made with respect tothe first electronic equipment, wherein the first electronic equipmentcomprises more than one signal generators, wherein a plurality ofidentifiers with respect to the stream are used in the first electronicequipment including a first identifier for identifying an interface withrespect to the stream within the first electronic equipment, output fromone of the signal generators, and a second identifier for identifying aninterface with respect to the stream between the first electronicequipment and the second electronic equipment for receiving the stream.18. A data transmission method of carrying out transmission/reception ofa stream by a plurality of electronic equipments, the data transmissionmethod comprising: a command generation step of generating a command fordiscovering an electronic equipment or equipments in which a connectioncan be made with respect to a first electronic equipment fortransmitting the stream by a third electronic equipment, different fromthe first electronic equipment and a second electronic equipment, whichis wireless-connected to the first electronic equipment and is capableof receiving the stream, wherein the first electronic equipmentcomprises more than one signal generators, wherein a plurality ofidentifiers with respect to the stream are used in the first electronicequipment including a first identifier for identifying an interface withrespect to the stream within the first electronic equipment, output fromone of the signal generators, and a second identifier for identifying aninterface with respect to the stream between the first electronicequipment and the second electronic equipment for receiving the stream.19. An electronic equipment constituting a data transmission system forcarrying out transmission/reception of a stream by a plurality ofelectronic equipments, wherein a first electronic equipment fortransmitting the stream and a second electronic equipment, which iswireless-connected to the first electronic equipment and is capable ofreceiving the stream, are different from each other, the firstelectronic equipment comprising: more than one signal generators,command generating means for generating a command for discovering anelectronic equipment or equipments in which a connection can be madewith respect to the first electronic equipment, and response analysingmeans for analysing a response, indicating information of the electronicequipment or equipments, transmitted from the first electronicequipment, wherein a plurality of identifiers with respect to the streamare used in the first electronic equipment including a first identifierfor identifying an interface with respect to the stream within the firstelectronic equipment, output from one of the signal generators, and asecond identifier for identifying an interface with respect to thestream between the first electronic equipment and the second electronicequipment for receiving the stream.